practice packet unit 11: kinetics and...

PRACTICE PACKET: UNIT 11 KINETICS AND EQUILIBRIUM

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Regents Chemistry:

Practice Packet Unit 11:

Kinetics and Equilibrium

Vocabulary: _______________ Lesson 1: __________________ Lesson 2: __________________ Lesson 3: __________________ Lesson 4: __________________ Lesson 5: __________________



Vocabulary

Reaction Rate: ____________________________________________________________________________________

Entropy: _________________________________________________________________________________________

Potential Energy: __________________________________________________________________________________

Activation energy: _________________________________________________________________________________

Le Chatelier’s Principle:_____________________________________________________________________________

Activated complex: ________________________________________________________________________________

Spontaneous reaction: _____________________________________________________________________________

catalyst: _________________________________________________________________________________________

heat of the reaction H: _____________________________________________________________________________

Heat of the reactants: _______________________________________________________________________________

Heat of the products: _______________________________________________________________________________

Collision Theory: ___________________________________________________________________________________

Effective Collision: __________________________________________________________________________________



LESSON 1: Collision Theory and Factors that Affect Reaction Rate

1. In order for a reaction to occur the particles must __________________with proper ______________

and ________________. Therefore, the more collisions the reactant particle have, the faster the rate.

2. Recall 5 ways to increase the rate of reaction. Be specific.

1. __________________________________________

2. __________________________________________

3. __________________________________________

4. __________________________________________

5. __________________________________________

3. Matches have the potential to burn on fire. But they will not without sufficient activation energy.

Explain what activation energy means and what type of activation energy the matches need.

4. Explain in terms of collision theory why increasing the temperature increases the rate of a reaction/

Regents Practice:

5. Which event must always occur for a chemical reaction to take place? a. formation of a precipitate b. formation of a gas c. effective collisions between reacting particles d. addition of a catalyst to the reaction system

6. Increasing the temperature increases the rate of a reaction by

a. lowering the activation energy b. increasing the activation energy c. lowering the frequency of effective collisions between reacting molecules d. increasing the frequency of effective collisions between reacting molecules

Objective:

Determine what factors affect the rate of reaction



7. After being ignited in a Bunsen burner flame, a piece of magnesium ribbon burns brightly, giving off heat and light. In this situation, the Bunsen burner flame provides

a. ionization energy b. activation energy c. heat of reaction d. heat of vaporization

8. As the number of effective collisions between reacting particles increases, the rate of reaction

a. Decreases b. increases c. remains the same

9. In most aqueous reactions as temperature increases, the effectiveness of collisions between reacting

particles a. Decreases b. increases c. remains the same

10. Given the reaction: Mg + 2 H2O Mg(OH)2 + H2 At which temperature will the reaction occur at the greatest rate? A) 25ºC B) 50ºC C) 75ºC D) 100ºC

11. A 5.0-gram sample of zinc and a 50.-milliliter sample of hydrochloric acid are used in a chemical reaction. Which combination of these samples has the fastest reaction rate?

a. a zinc strip and 1.0 M HCl(aq) b. a zinc strip and 3.0 M HCl(aq) c. zinc powder and 1.0 M HCl(aq) d. zinc powder and 3.0 M HCl(aq)

12. A 1.0-gram piece of zinc reacts with 5 milliliters of HCl(aq). Which of these conditions of concentration and temperature would produce the greatest rate of reaction?

a. 1.0 M HCl(aq) at 20.°C b. 1.0 M HCl(aq) at 40.°C c. 2.0 M HCl(aq) at 20.° d. 2.0 M HCl(aq) at 40.°C

13. At STP, which 4.0-gram zinc sample will react fastest with dilute hydrochloric acid? a. lump c. bar b. powdered d. sheet metal



14. Given the reaction: Fe(s) + 2 HCl(aq) FeCl2(aq) + H2(g)

In this reaction, 5 grams of powdered iron will react faster than a 1-gram piece of solid iron because the powdered iron

a. has less surface area b. has more surface area c. is less dense d. D) is more dense

15. Which statement best explains the role of a catalyst in a chemical reaction?

a. A catalyst is added as an additional reactant and is consumed but not regenerated. b. A catalyst limits the amount of reactants used. c. A catalyst changes the kinds of products produced. d. A catalyst provides an alternate reaction pathway that requires less activation energy.

16. Which change would most likely increase the rate of a chemical reaction?

a. decreasing a reactant's concentration b. decreasing a reactant's surface area c. cooling the reaction mixture d. adding a catalyst to the reaction mixture

ADDITIONAL PRACTICE LESSON 1:

1. In terms of collisions, why does an increase in concentration lead to an increase in the rate of the

reaction?

2. Decreasing the temperature decreases the rate of a reaction by

a. lowering the activation energy b. increasing the activation energy c. lowering the frequency of effective

collisions between reacting molecules d. increasing the frequency of effective

collisions between reacting molecules

3. A 5.0-gram sample of zinc and a 50.-milliliter sample of hydrochloric acid are used in a chemical reaction. Which combination of these samples has the fastest reaction rate?

a. a zinc strip and 1.0 M HCl(aq) b. a zinc strip and 3.0 M HCl(aq) c. zinc powder and 1.0 M HCl(aq) d. zinc powder and 3.0 M HCl(aq)

ASSESS YOURSELF ON THIS LESSON: _________/16 If you missed more than 2, do the Additional Practice. If not, go on to the next hw video!!!

ASSESS YOURSELF ON THIS ADDITIONAL PRACTICE: _________/3 If you missed any questions you should see me for extra help and/or re-watch the lesson video

assignment



LESSON 2: Energy Changes in Chemical Reactions Review

Key Ideas:

Enthalpy is a fancy word for __________ of reaction.

All exothermic reactions are given a _____________ value on Table I.

Exothermic reactions are ________ stable then endothermic reactions.

Combustion reactions are the first 6 reaction on table I. What reactant do they have in common?

___

The last 6 of 7 reactions on table I show substances dissolving. What reactant do they have in

common? __

______________ of a reaction measured by subtracting: __________________ minus __________________.

These values can be found on table ________.

1. How much heat is required to produce 1 mole of C2H2? _______________________________________

2. How much heat is required to produce 2 moles of C2H2? ______________________________________

3. If you reverse a reaction what happens to the magnitude of ∆H? What happens to the sign?

4. If the ∆H for a given forward reaction is positive, will the reverse reaction be endothermic or exothermic?

5. Is the decomposition of C2H6 endothermic or exothermic? ____________________________________

Reaction ∆H (kJ) Endothermic and Exothermic

CH4(g) + 2O2(g) → CO2(g) + 2H2O(l)

2H2(g) + O2(g) → 2H2O(g)

C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l)

N2(g) + 3H2(g) → 2NH3(g)

2Al2O3(s) → 4Al(s) + 3O2(g)

*4NO(g) → 2N2(g) + 2O2(g)

Potassium nitrate dissociating into a positive potassium ion and a negative nitrate ion

Objective:

Determine what factors affect the rate of reaction



Regents Practice: 1. Given the equation representing a reaction:

CH4(g) + 2O2(g) 2H2O(g) + CO2(g) + heat Which statement is true about energy?

A) The reaction is exothermic because it releases heat.

B) The reaction is exothermic because it absorbs heat.

C) The reaction is endothermic because it releases heat.

D) The reaction is endothermic because it absorbs heat.

2. Which balanced equation represents an endothermic reaction?

A) C(s) + O2(g) CO2(g) B) CH4(g) + 2O2(g) CO2(g) + 2H2O( ) C) N2(g) + 3H2(g) 2NH3(g) D) N2(g) + O2(g)2NO(g)

3. According to Table I, which salt releases energy as it dissolves?

A) KNO3 B) LiBr C) NH4NO3 D) NaCl

4. Given the balanced equation representing a reaction at 101.3 kPa and 298 K:

N2(g) + 3H2(g) 2NH3(g) + 91.8 kJ Which statement is true about this reaction?

A) It is exothermic and H equals –91.8 kJ.

B) It is exothermic and H equals +91.8 kJ.

C) It is endothermic and H equals –91.8 kJ.

D) It is endothermic and H equals +91.8 kJ.

5. Which expression represents the H for a chemical reaction in terms of the potential energy, PE, of its products and reactants?

A) PE of products + PE of reactants

B) PE of products – PE of reactants

C) PE of products × PE of reactants

D) PE of products / PE of reactants

6. Given the balanced equation: 4Fe(s) + 3O2(g) 2Fe2O3(s) + 1640 kJ Which phrase best describes this reaction?

A) endothermic with H = +1640 kJ

B) endothermic with H = –1640 kJ

C) exothermic with H = +1640 kJ

D) exothermic with H = –1640 k


Reaction ∆H (kJ) Endothermic and Exothermic

CO2(g) → C(s) + O2(g)

NH4Cl(s) → NH4+(aq) + Cl-(aq)

2CO2(g) + 4H2O(l) → 2CH3OH(l) + 3O2(g)

Sodium hydroxide dissociating into a positive sodium ion and a negative hydroxide ion


ASSESS YOURSELF ON THIS ADDITIONAL PRACTICE: _________/4 If you missed any questions you should see me for extra help and/or re-watch the lesson video assignment



LESSON 3: POTENTIAL ENERGY DIAGRAMS

Key Ideas:

The _____________ energy is the energy needed to start a reaction. It is

labeled on the diagram with ____.

The activated complex is the point with the _________ energy on the graph.

It is labeled on the diagram with ____.

The ________________ are always at the beginning of a reaction and is labeled

–here with a ____.

The _______________ are always at the end of a reaction and is labeled here with a ____.

The enthalpy of the reaction (or heat) is the _______________ between the products and the reactants

and is labeled here with a ____.

Reactions that have products with higher energy than reactants, such as the one in the diagram,

are _______thermic reactions.

Objective:

Label potential energy diagrams and determine the type of diagram represented



1. On the diagram to the right find the value of the

following statements in kJ for the uncatalyzed

reaction:

a. Reactants PE: _____

b. Products PE: _____

c. Activated complex PE: _____

d. Activation Energy: _____

e. Heat of Reaction: _____

f. Activation Energy of the

reverse reaction: _____

g. Heat of reverse reaction: _____

2. Is the diagram above depicting an endothermic or exothermic reaction? Defend your answer.

3. On the diagram above, sketch the pathway for the catalyzed reaction. Record the new values below and

circle those that DID NOT change from the values for the uncatalyzed reaction above:

a. Reactants PE: _____

b. Products PE: _____

c. Activated complex PE: _____

d. Activation Energy: _____

e. Heat of Reaction: _____



4. For the reaction on table I that creates Aluminum oxide, write the reaction and the ΔH then sketch the PE

curves:

a. FORWARD (synthesis) b. REVERSE (decomposition)

RXN:____________________ ____________ ______________ ________________________

ΔH = _______________ ΔH = _______________________

ADDITIONAL PRACTICE LESSON 3: 1. Using the reactions on table I, sketch a graph for the reaction that produces nitrogen dioxide (NO2):

2. Label the graphs with the following: heat of reactants and products, activation energy, activated

complex, heat of the reaction H.


ASSESS YOURSELF ON THIS ADDITIONAL PRACTICE: _________/4 If you missed any questions you should see me for extra help and/or re-watch the lesson video assignment



LESSON 4: EQUILIBRIUM & ENTROPY

Key Ideas - Equilibrium:

Equilibrium requires the rate that the reaction forms products must be ______________ the rate that the

reaction forms reactants.

Equilibrium states that a reversible reaction has equal _____________ not necessarily equal amounts.

Equilibrium can be between ______________, e.g, the rate of freezing = rate of melting.

In solution equilibrium, rate of ________________________________ = rate of ______________________________.

Equilibrium can only be achieved in a ___________________________ (closed or open) system.

1. What condition(s) describe a system at equilibrium?

Equal _____________________; Constant _______________________

2. On the diagram to the right, label the time where equilibrium is achieved in the system.

3. Write the equation for the system at equilibrium.

4. Why is this described as “dynamic” equilibrium

Objective:

Determine if a reaction is spontaneous

Determine if entropy increases or decreases in a reaction



Regents Practice:

1. What occurs when a reaction reaches equilibrium? A) The concentration of the reactants increases. B) The concentration of the products increases. C) The rate of the forward reaction is equal to the rate of the reverse reaction. D) The rate of the forward reaction is slower than the rate of the reverse reaction.

2. Which changes can reach dynamic equilibrium? A) nuclear changes, only B) chemical changes, only C) nuclear and physical changes D) chemical and physical changes

3. Given the equation representing a system at equilibrium:

PCl5(g) PCl3(g) + Cl2(g)

Which statement describes this system:

A) The concentration of PCl5(g) is increasing. B) The concentration of PCl5(g) is decreasing. C) The concentrations of PCl5(g) and PCl3(g) are equal. D) The concentrations of PCl5(g) and PCl3(g) are constant.

4. A reaction reaches equilibrium at 100 °C. The equation and graph representing this reaction are shown below:

The graph shows that the reaction is at equilibrium after 60 seconds because the concentration of both NO2(g) and N2O4(g) are A) increasing B) decreasing C) constant D) zero



Key Ideas - Entropy:

Entropy measures the ______________ in a system.

The _______________ phase has the most entropy because its particles move the most.

The more particles a system has, the __________ entropy it has. This is a direct relationship.

Nature favors reactions which result in ____________ (higher or lower) entropy and ________________ (higher or

lower) energy, i.e., _____ thermic where the PE of the products is _______________________ (greater or less than)

the PE of the reactants.

Rank order the following states of matter (solid, liquid, gas, aqueous) in terms of entropy from lowest to highest: Least entropy: _________________ ________________ ________________ Most entropy: _________________ Determine whether the following reactions show an increase or decrease in entropy based on the individual states (s), (l), (aq), (g) within the reaction.

1) H2O(g) H2O(l) _____________________________

2) NaCl(s) Na+(aq) + Cl-(aq) _____________________________

3) KCl(s) KCl(l) _____________________________

4) CO2(s) CO2(g) _____________________________

5) H+(aq) + C2H3O2

-(aq) HC2H3O2(l) _____________________________

6) C(s) + O2(g) CO2(g) _____________________________

7) Ag+(aq) + Cl-(aq) AgCl(s) _____________________________

8) 2N2O5(g) 4NO2(g) + O2(g) _____________________________

9) 2Al(s) + 3I2(s) 2AlI3(s) _____________________________

10) 2KClO3(s) 2KCl(s) + 3O2(g) _____________________________



11. Fill in the table below.

Reaction Change in Energy (endo/exothermic)

Entropy (Increases or decreases)

a.) CO2(s) CO2(g)

b.) I2(g) I2(s)

c.) C(s) + O2(g) CO2(g)

d.) 4Al(s) + 2O2(g) 2 Al2O3(s)

Questions:

1. Which substance has the highest entropy?

a. Xe(g) b. S(s) c. Hg(s)

2. Which substance has the lowest entropy?

a. H2O at -120˚C b. H2O at 0˚C c. H2O at 100˚C

3. When a system becomes less random the entropy

a. Increases b. decreases c. remains the same

4. Which shows an increase in entropy?

a. H2O(s) H2O(l) b. H2O(g) H2O(l) c. H2O(l) H2O(s)

5. In the following reaction, the entropy is CaCO3(s) CaO(s) and CO2(g)

a. Increasing b. decreasing c. remaining the same

6. A chemical reaction is spontaneous if

a. There is a gain of energy and entropy increases

b. There is a gain of energy and entropy decreases

c. There is a loss of energy and entropy increases

d. There is a loss of energy and entropy decreases




LESSON 5: LECHATELIERS PRINCIPLE

Key Ideas:

When changes are made to a system at equilibrium the system will react to reduce the stress as follows:

When a reactant is added the reaction shifts away from the reactant to make more _________________.

When a product is added the reaction shifts away from the product to make more __________________.

When a reactant is taken the reaction shifts _________________ the reactant to restore it.

When a product is taken the reaction shifts _________________ the product to restore it.

When heat is added to a reaction the reaction shifts _________________ from the heat, much like a reactant or

product. Therefore if heat is removed (or taken) the reaction shifts ____________________ heat.

When a gaseous system increases in pressure or decreases in volume the system can hold fewer moles.

Therefore the reaction shifts towards the side with _________________ moles.

Catalysts affect both forward and reverse reaction rates _____________________, therefore have ___________________

on equilibrium.

1. Circle which direction the equilibrium will shift towards to relieve the stress:

2NH3(g) N2(g) + 3H2(g) + heat

a. Ammonia is added left right no effect b. Nitrogen is added left right no effect c. Hydrogen is added left right no effect d. Heat is added left right no effect e. Ammonia is removed left right no effect f. Nitrogen is removed left right no effect g. Hydrogen is removed left right no effect h. Heat is removed left right no effect i. Pressure is increased left right no effect j. Pressure is decreased left right no effect k. A catalyst is added left right no effect

Objective:

Determine the shift in equilibrium when a stress is placed on a system

Determine the change in concentration when a stress is placed on a system



2. Circle what will happen to the Nitrogen to relieve the stress: N2(g) + 3H2(g) + heat 2NH3(g)

a. Ammonia is removed increase decrease remain the same b. Heat is added increase decrease remain the same c. Pressure is increased increase decrease remain the same d. Heat is removed increase decrease remain the same e. Ammonia is added increase decrease remain the same f. Hydrogen is removed increase decrease remain the same g. A catalyst is used increase decrease remain the same h. Pressure is decreased increase decrease remain the same i. Hydrogen is added increase decrease remain the same

3. In a closed soda bottle the following equilibrium exists: H3O+(aq) + HCO3

-(aq) + heat 2H2O(l) + CO2(g)

a. When the cap is opened, the pressure decreases. Which way does the reaction shift?

b. Will opening the cap result in more or less carbon dioxide dissolved in the soda?

c. When the soda is left out on a hot day, which way does the equilibrium reaction shift?

d. Will heating the soda result in less or more carbon dioxide dissolved in the soda?

e. Why do soda companies recommend storing soda at cool temperatures with the cap on tight?

4. List four changes you could make to the system in order to produce more phosphorous pentachloride:

Cl2(g) + PCl3(g) + heat PCl5(g)

_________________________________________________ _____________________________________________________

________________________________________________ _____________________________________________________

ASSESS YOURSELF ON THIS LESSON: _________/29 If you missed more than 3, do the Additional Practice. If not, go on to the ticket to the test!!!




1. Indicate how each of the following changes affects the amount of each gas in the system below, for

which Hreaction = +9.9 kcal. H2(g) + CO2(g) H2O(g) + CO(g)

a) addition of CO2 ___ ___ ___

b) addition of H2O ___ ___ ___

c) addition of a catalyst ___ ___ ___ ___

d) increase in temperature ___ ___ ___ ___

e) decrease in the volume of the container ___ ___ ___ ___

2. How will the amount of chemicals at equilibrium be affected by each of the following: 2N2O(g) + O2(g) 4NO(g) a) adding N2O ___ ___

b) removing O2 ___ ___

c) increasing the volume of the container ___ ___ ___

d) adding a catalyst ___ ___ ___

3. How will the concentration of each chemical be affected by 4NH3(g) + 3O2(g) 2N2(g) + 6H2O(l)

a) adding O2 to the system ___ ___ ___

b) adding N2 to the system ___ ___ ___

c) removing H2O from the system ___ ___ ___

d) decreasing the volume of the container ___ ___ ___ ___




4. Match the change to the equilibrium system below with the letter of the appropriate response. Each letter can

be used once, more than once, or not at all.

2SO2(g) + O2(g) 2SO3(g)

_____ 1) O2 is added to the reaction a) The equilibrium shifts to the right

_____ 2) SO3 is removed from the reaction b) The equilibrium shifts to the left

_____ 3) SO3 is added to the reaction c) there is no change in the equilibrium

_____ 4) The pressure is increased

ASSESS YOURSELF ON THIS ADDITIONAL PRACTICE: _________/4 If you missed MORE THAN one you should see me for extra help and/or re-watch the lesson video

assignment



TICKET TO THE TEST Unit 11 Kinetics

Directions: Answer all questions and show all work. Use your notebook, homework, and videos to help you review all the concepts. I might ask you to come up with your own examples. Come after school if you have questions. You should be supplying me with anything you think may be tested. Then, use this as a study sheet. It is due BEFORE the test. No late tickets will be accepted. This could be worth up to 5 points on the test. The more you show, the more points you get, the more you might actually remember!

1. Explain what two parameters are needed in order for a reaction to be considered effective. Draw

examples of reactions and give analogies. Effective collisions need proper ____________________ and _______________________

Analogy:

2. List and explain the five factors that affect the rate of reaction and how they do it:

a. ______________________________________________________________________________

b. ______________________________________________________________________________

c. ______________________________________________________________________________

d. ______________________________________________________________________________

e. ______________________________________________________________________________

3. Go back into your homework and class packets and find a question about reaction rates that you got wrong the first time. Give the question and explain the correct answer:

4. Pretend you are the teacher. Create a question that you could ask in order to judge if your students know what factors affect reaction rates and why. Create the question and answer. Question: Answer:



5. Using table I give examples for the following:

a. Endothermic reaction: ___________________________________________________________

b. Exothermic reaction: ____________________________________________________________

c. Doubling a reactions and finding enthalpy values:

d. Reversing a reaction and finding enthalpy values:

6. Draw an exothermic and an endothermic potential energy diagram and label with the following with a-e:

a. Reactants b. Products c. Activated complex d. Activation energy e. Heat of reaction

7. Compare and contrast your two drawings.

8. If values were given, how could you calculate the heat of reaction?

HEAT OF REACTION =

9. What factors (a-e) change when a catalyst is added? Why? What does a catalyst do? Factors that change with a catalyst: _____________________________________________________ Role of a catalyst: ____________________________________________________________________

10. Why do these PE diagrams have a “bump” even though energy is sometimes exothermic and releasing?

11. Give examples of ACTIVATION ENERGY: ______________________________________________

exo endo



12. If you were the teacher, what additional question would you ask to measure a student’s understanding of PE diagrams? Question: Answer:

13. Define entropy: ENTROPY: _________________________________________________

14. Give examples of:

a. A reaction where entropy increases because of the phases:

b. A reaction where entropy increases because of amounts:

c. A reaction where entropy decreases because of the phases:

d. A reaction where entropy decreases because of amounts:

15. How do changes in temperature affect entropy?

16. What two factors make reactions spontaneous? Give an analogy. SPONTANEUOS REACTIONS ________________________________________________________ Example:

17. What is equal about equilibrium? _________________



18. What special sign do equilibrium reactions get?

19. At equilibrium, what happens to the quantities of reactants and products? ________________________

20. Give a word that represents a solution at equilibrium:

_______________________________ means a solution is at equilibrium.

21. Using the following reaction, construct questions about concentration, pressure, volume, catalyst, and temperature changes on the system and then answer them.

53 kJ + H2(g) + I2(g) 2HI(g) Question Answer

a. _______________________________ __________________________________________

b. _______________________________ __________________________________________

c. _______________________________ __________________________________________

d. _______________________________ __________________________________________

e. _______________________________ __________________________________________

22. What topics do you still need to study after completing this packet? Show me work for additional

examples you have done: What is your goal grade on this kinetics test? Be reasonable. ____________________ Do you really feel you did enough to achieve that goal? Why or why not?

practice packet unit 11: kinetics and...

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